Study details and key findings

For the study, researchers analyzed data from over 9 million U.K. adults from 2000 to 2019. In particular, they compared data from 30,039 adults who had been diagnosed with ADHD and 300,390 controls who were similar in age, sex, and primary care practice.

Overall, the researchers found that people who had been diagnosed with ADHD had significantly shorter life expectancies than the general population. Men diagnosed with ADHD had a reduction in life expectancy of 4.5 to nine years, with an average of 6.8 years. Women with ADHD had a reduction in life expectancy of 6.5 to 11 years, with and an average of 8.6 years.

Aside from shorter life expectancy, the researchers also found that ADHD was associated with a higher risk of mental health issues, such as depression, anxiety, personality disorders, self-harm, and suicide. Autism, intellectual disabilities, physical health problems, and harmful habits like smoking or "potentially harmful alcohol use" were also more common among people with ADHD.

"We know that people with ADHD have higher suicide rates, unfortunately," said Joshua Stott, a professor of aging and clinical psychology at University College London and one of the study's authors. "They are also more likely to engage in risky behaviors like smoking, drinking and actually binge eating probably as well."

"Although many people with ADHD live long and healthy lives, our finding that on average they are living shorter lives than they should indicates unmet support needs," said Liz O'Nions, honorary research fellow in clinical, education, and health psychology at University College London and the study's lead author. "It is crucial that we find out the reasons behind premature deaths so we can develop strategies to prevent these in the future."

Similarly, a 2019 study that used actuarial tables to predict life expectancy found that adults who had been diagnosed with ADHD in childhood had an 8.4-year reduction in life expectancy compared to the general population. According to the researchers, this reduction may have been due to lower education and income, higher rates of smoking and alcohol consumption, and reduced sleep among people with ADHD.

Russell Barkley, a retired professor of clinical psychology at Virginia Commonwealth University and the lead author of the 2019 study, said ADHD is not just a childhood disorder, but a lifelong condition. "To me, the best analog is diabetes," he said. "This is a disorder that you've got to manage, like high blood pressure, like cholesterol and diabetes. You've got to treat this for life."

Stephen Hinshaw, a professor of psychology at the University of California, Berkeley, said the new study was a "major finding" as the first analysis of deaths of patients diagnosed with ADHD. However, he noted that it was unfortunate that the patients' causes of death were not included in the research.

"There are risk factors to work on," Hinshaw said. "That is the key limitation of the study, because it would be really important to know, in terms of prevention, should we be focused on suicidality? Better diet and exercise? Depression?"

According to Stott, healthcare systems may need to adjust how they operate to better serve people with ADHD, who may experience sensory sensitivity or have difficulty managing time or communicating with clinicians during short appointments. He also said he hoped treatments for substance abuse or depression could be adapted for those with ADHD.

"If it's about systems, it's malleable," he said. "This doesn't have to be."